Electric power systems often are used to produce electric power for different kinds of electronic equipment having different functions and electrical requirements. For example, residential photovoltaic (PV) systems can comprise a plurality a PV arrays each comprising a plurality of PV cells in series to provide electric power for a variety of residential appliances requiring different voltages, currents and polarities. PV systems process DC power since PV cells produce variable DC output.
Electric power conversion systems are used to supply subsystems with the required electrical energy by converting electrical energy supplied or generated into the specific form needed. For PV-based systems, for example, the voltage levels produced by the PV array is generally smaller than the voltage level requirements for residential appliances and therefore must be increased by the power conversion system.
Known DC-DC converters comprise a switch network for receiving an unregulated input voltage that is coupled to a resonant circuit including a capacitor, inductor and a single transformer that drives an output capacitor across which a load is placed in field use. Such known DC-DC converters have several limitations. For example, achieving peak gain is associated with a smaller inductance index, which indicates a higher magnetizing current that results in increased conduction loss and thus lower overall efficiency. There is thus a tradeoff between DC gain and efficiency.